Info Catalog octave: Concatenating Strings octave: Creating Strings

octave: Converting Numerical Data to Strings

 
 5.3.2 Converting Numerical Data to Strings
 ------------------------------------------
 
 Strings::) which cast numerical data to the corresponding ASCII
 characters, there are several functions that format numerical data as
 strings.  ‘mat2str’ and ‘num2str’ convert real or complex matrices,
 while ‘int2str’ converts integer matrices.  ‘int2str’ takes the real
 part of complex values and round fractional values to integer.  A more
 flexible way to format numerical data as strings is the ‘sprintf’
 function (Formatted Output, sprintf XREFsprintf.).
 
  -- : S = mat2str (X, N)
  -- : S = mat2str (X, N, "class")
      Format real, complex, and logical matrices as strings.
 
      The returned string may be used to reconstruct the original matrix
      by using the ‘eval’ function.
 
      The precision of the values is given by N.  If N is a scalar then
      both real and imaginary parts of the matrix are printed to the same
      precision.  Otherwise ‘N(1)’ defines the precision of the real part
      and ‘N(2)’ defines the precision of the imaginary part.  The
      default for N is 15.
 
      If the argument "class" is given then the class of X is included in
      the string in such a way that ‘eval’ will result in the
      construction of a matrix of the same class.
 
           mat2str ([ -1/3 + i/7; 1/3 - i/7 ], [4 2])
                ⇒ "[-0.3333+0.14i;0.3333-0.14i]"
 
           mat2str ([ -1/3 +i/7; 1/3 -i/7 ], [4 2])
                ⇒ "[-0.3333+0i 0+0.14i;0.3333+0i -0-0.14i]"
 
           mat2str (int16 ([1 -1]), "class")
                ⇒ "int16([1 -1])"
 
           mat2str (logical (eye (2)))
                ⇒ "[true false;false true]"
 
           isequal (x, eval (mat2str (x)))
                ⇒ 1
 
      See also: sprintf XREFsprintf, num2str XREFnum2str,
      int2str XREFint2str.
 
  -- : num2str (X)
  -- : num2str (X, PRECISION)
  -- : num2str (X, FORMAT)
      Convert a number (or array) to a string (or a character array).
 
      The optional second argument may either give the number of
      significant digits (PRECISION) to be used in the output or a format
      template string (FORMAT) as in ‘sprintf’ (Formatted
      Output).  ‘num2str’ can also process complex numbers.
 
      Examples:
 
           num2str (123.456)
                ⇒ "123.46"
 
           num2str (123.456, 4)
                ⇒ "123.5"
 
           s = num2str ([1, 1.34; 3, 3.56], "%5.1f")
                ⇒ s =
                   1.0  1.3
                   3.0  3.6
           whos s
                ⇒
                 Attr Name        Size                     Bytes  Class
                 ==== ====        ====                     =====  =====
                      s           2x8                         16  char
 
           num2str (1.234 + 27.3i)
                ⇒ "1.234+27.3i"
 
      The ‘num2str’ function is not very flexible.  For better control
      over the results, use ‘sprintf’ (Formatted Output).
 
      Programming Notes:
 
      For MATLAB compatibility, leading spaces are stripped before
      returning the string.
 
      Integers larger than ‘flintmax’ may not be displayed correctly.
 
      For complex X, the format string may only contain one output
      conversion specification and nothing else.  Otherwise, results will
      be unpredictable.
 
      Any optional FORMAT specified by the programmer is used without
      modification.  This is in contrast to MATLAB which tampers with the
      FORMAT based on internal heuristics.
 
      See also: sprintf XREFsprintf, int2str XREFint2str,
      mat2str XREFmat2str.
 
  -- : int2str (N)
      Convert an integer (or array of integers) to a string (or a
      character array).
 
           int2str (123)
                ⇒ "123"
 
           s = int2str ([1, 2, 3; 4, 5, 6])
                ⇒ s =
                   1  2  3
                   4  5  6
 
           whos s
                ⇒
                 Attr Name        Size                     Bytes  Class
                 ==== ====        ====                     =====  =====
                      s           2x7                         14  char
 
      This function is not very flexible.  For better control over the
      results, use ‘sprintf’ (Formatted Output).
 
      Programming Notes:
 
      Non-integers are rounded to integers before display.  Only the real
      part of complex numbers is displayed.
 
      See also: sprintf XREFsprintf, num2str XREFnum2str,
      mat2str XREFmat2str.
 

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